I agree with ruben's first two points.
I have been working with SEO for over 10 years and although I was initially skeptical, I have never seen a difference between the ranking ability of hyphenated and non-hyphenated names. I always go for the non-hyphenated name if it is available, but do register hyphenated names when the first choice is not available. You will see a mix of both in Google search results. Like ruben said, it is easier to remember a non-hyphenated name.
Always go for the .com if it is available. .net and .org can rank equally well. The jury is still out on .info and I would not buy one.
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." -- Benjamin Franklin